This invention relates to a printing control apparatus and method and, more particularly, to a printing control apparatus and method through which a plurality of sets of copies printed on both sides can be obtained as entirely separate sets of copies in a system comprising an information processing apparatus such as a personal computer and a printing apparatus not having a function for printing sets of copies individually.
When an information processing apparatus outputs a plurality of sets of copies of one document which includes text, images or tables, the output can be obtained by a specified plurality of sheets at a time per page (per sheet of paper in case of double-sided printing) or the output can be obtained collectively per each set of copies. Methods of implementing printing on a per-copy basis in which output is obtained collectively per each set of copies include a method carried out by the printing apparatus and a method carried out by the information processing apparatus.
A method of printing on a per-copy basis using a printing apparatus can be either of two types. According to the first method, all print data constituting one print job accepted from the information processing apparatus is accumulated in the printing apparatus, which proceeds to repeatedly output the data of this job a number of times equivalent to the specified number of copies desired. The second method utilizes a device such as a sorter that changes the destination of the output on a per-copy basis. In the case of the first method, it is necessary for the printing apparatus to have a memory or hard disk for accumulating the print data. The second method requires a sorter. In either case, cost is a problem since printing on a per-copy basis is implemented by the printing apparatus. It is generally the case that printers are incapable of printing on such a per-copy basis.
The practice in the prior art, therefore, is to adopt the method in which printing on a per-copy basis is carried out by the information processing apparatus. An example of a conventional approach for printing on a per-copy basis using an information processing apparatus involves transmitting the print data of one print job to the printing apparatus repeatedly a number of times equivalent to the number of copies that should be output. In order to carry out this method, it is necessary that the application software that executes printing perform processing for the purpose of implementing this method. Consider a case where double-sided printing is performed by printing on per-copy basis implemented by the application according to the prior art. If the number of pages in the document to be printed in this case is odd, a problem which arises is that the first page of the next set of copies of the document will be printed on the reverse side of the last page of the first set of copies of the document. This means that the output product cannot be separated into separate sets of copies.
An example of a method of solving this problem is such that when N copies of a document are to be printed, N print jobs, each of which is for printing one copy of the document, are generated and the N print jobs are transmitted to the printing apparatus. According to this method, printing is performed on the basis of the independent print jobs one copy at a time. As a result, the output product can be separated into discrete sets of copies by discharging the paper from the printing apparatus at the boundary between mutually adjacent sets of copies, i.e., at the moment one job ends.
In a case where a print job is generated per each set of copies, however, each print job must be canceled or suspended in order to cancel or suspend the printing of a document currently being printed.
Further, in a case where a document is to be printed from a printing apparatus shared on a network, it is possible that a print job that has been transmitted from another client will be inserted between print jobs that print a plurality of copies of a document. This means that one must check to determine whether the output product of another client has been included in the output product consisting of the plurality of copies. In addition, if another client is also printing out a plurality of copies of a document, print jobs the number of which is equal to the number of output copies of each document will be generated. As a result, the copies of the two types of documents will be discharged into the catch tray of the printing apparatus in a mixed state, though the copies of each document will be discharged in individual sets. It is obvious that if clients desiring to print plural copies of documents using the same printing apparatus increase, arranging the output products will be an extremely complicated task.